Hello all! This is my first post and it shall not be my last! I just picked up my '91 4Runner SR5 V6 automatic a week ago for $2,000. It's not perfect, but with only 122K miles on it, I'm quite pleased with it. Here's my problem, after I bought the car and was driving home on the freeway, I noticed that my tranny wasn't shifting into OD. I checked the OD switch, it was on. In the week that I've had it, it has yet to shift into OD, save for 2 occasions. Both times, I had been driving the truck for several hours and, out of nowhere, it just shifted into OD with a bit of a jolt. I've added AT fluid. Someone told me that it could be the transmission solenoid, but I also had someone tell me that since it did actually shift into OD a few times that it's probably not the solenoid, but a clogged transmission filter. Anyway, could someone tell me if they've had a similar problem and how they rectified it? And, if it is the solenoid, where can I get one and how much will it cost me? I have a friend who will do the work for me. Any help would be GREATLY appreciated.

Thanks!
-Joe R.

P.S.
The coolant seems to be low (not low enough for it to be running too hot or anything), but could this be the problem? I know the tranny won't shift into OD until the coolant warms up.

The tranny won't shift into O/D until the fluid temp reaches approximately 170 degrees Fahrenheit. Neither will your torque converter lock up, for the same reason. Howerver, it shouldn't take several hours of driving to get it into O/D.

You could have a weak solenoid. I'd suspect that it is more likely you have gunk in the valvebody and the O/D solenoid attached to that valve is having trouble moving it.

These transmissions don't tolerate the fluid level to be out of the 'normal' range, very well. So make sure you check the tranny fluid: engine and tranny fully warmed up to operating temp, on level ground, engine idling, parking brake set, tranny in Park.

If it's a little low you should add fluid until it's within the normal range. If you want to try and clean all the fluid passages inside, you 'may' want to try an additive called Trans-X. Some on here may advise against it. However, I have used it in two different vehicles (including my 92 3.0 auto tranny 4Runner) with good success.

I think the best thing to do is just 'drive it'. If it has been sitting, some of the gunk may have attached itself to critical parts. Dexron-III fluid ( the type you use in these trannys) has some detergent properties.

Let us know how it goes.

Mike in AR

Hello again! Thanks for all the advice, Mike. I tried the Trans-X. There were a couple different formulas at Auto Zone. I bought the one that said "Stop-Leak and Tune Up" in the bottle that looks like a quart of oil. I added half of the bottle to the tranny fluid shaft to no avail as of yet. If this was indeed the problem, how long does it take to see (feel) results? Should I add more or should I just have my buddy just drain the old fluid, put on a new tranny filter, and add new fluid? If we do that and there's still no change, how much would I be able to get that solenoid for and where from? Thanks again for all your help, it's greatly appriciated!

-Joe R.
'91 4Runner SR5 V6

You'll have to drive it some. The action of the solenoid/valve working inside the valvebody along with the additive ,should eventually free it up... if it's just 'gunked up'.

Half the bottle should be enough. Just need to be sure the final fluid level is within the acceptable zone -- not over or under full.

Drive it a week and see what happens. It will take some time for the additive to do its stuff,, if it's going to.

Getting the 'correct' solenoid for your particular model of tranny might be a dealer-only source.

I bought my 92 3.0 with the A340H auto with 145,000 miles on it. I'm not sure if the tranny had been rebuilt, but it appeared that at some point, at least, the pan had been pulled. I can see what appears to be 'new' sealer around the lip of the pan where it meets the tranny case. That said -- my tranny now has 183,000 miles on it and the solenoids still appear to be operating properly.

I also choose to run 12 ounces of Prolong Automatic Transmission treatment in my tranny , as well as a small amount of Trans-X. Some may have the opinion that additives do little for component life, but I have been sold on Prolong products since 1997. I bought a 90 model Corolla,, 103,000 miles on the 4-cylinder. The valves were kinda noisy. I put a bottle of Prolong Engine Treatment in at every oil change. The valves quited right down and I never had an engine problem. Traded it in with 189,000 miles on it.

(Another unsolicited testimonial)

Mike in AR

look your cooling system over see if you can find the leak...id slap a t-stat in it as well to eliminate the obvious but if its stuck open or gone your engine might not come up to proper operating temp...its been chilly in IL over the pat few weeks...ive found the toyota autos dont take well to xmsn 'snake oils' so do a trans service and go back in w/ some quality dextron 3...

I am also having the same problem in my 91 automatic. Will randomly shift to over drive, then with drop out of it about 5 mins later. Thermo gauge sits a little below half, also heard could be a solenoid in tranny or tranny temp sensor. Curious on how to tell what temp it’s sitting at being it has to be 170 to run properly

If it comes on at all it's probably not a temp issue, but the OD solenoid in the trans.
What engine?

Time for a valvebody clean and seal replacement. stuck or slow solenoid and pistons cause shifts problems in most cases.

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